Preparation and characterization of CoWO4/CoMn2O4 nanoflakes composites on Ni foam for electrochemical supercapacitor applications

A simple synthesis method for hybrid transition metal oxides is important for their application in electrode materials. In this present work, we reported one-pot hydrothermal method to synthesize CoWO4/CoMn2O4 nanoflake composites. The prepared CoWO4/CoMn2O4 nanoflakes composite electrodes were comprehensively characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Electrochemical capacitive behaviour of the electrodes fabricated on a nickel foam substrate were evaluated by cyclic voltammetry (CV), galvanostatic charge/discharge cycling (GCD) and electrochemical impedance spectroscopy (EIS) techniques in 3 M KOH aqueous electrolyte solution. The results show that the CoWO4/CoMn2O4 nanoflake composites possess an excellent specific capacitance of 2259.6 F g(-1) at the current density of 2 A g(-1). In addition, the CoWO4/CoMn2O4 nanoflakes show excellent cycling stability (92.6 % capacity retention after 3000 cycles) than CoWO4(78.3%) and CoMn2O4 (85.7%). These attractive results suggest that these CoWO4/CoMn2O4 nanoflake composites have great potential as an electrode material for the next generation of high-performance electrochemical supercapacitors.